Systems using debit cards are known. For example, it is known to use magnetic cards having data transfer means in the form of magnetic tracks which are passed beneath read/write heads in a fixed station, or memory cards in which the transfer means are electrical contacts which make connection by means of pressure applied in the read heads of fixed processing stations.
These cards need to be inserted into a fixed processing station in order to be connected to internal components of said fixed station by means of mechanical contacts which give rise to problems of reliability insofar as the contacts may oxidize, become dirty, or damaged.
In addition, such a system slows down a stream of users.